Is Trust Given Or Earned?

Ok, so I know that these days it can be extremely, extremely hard to trust people. With all the cheating and scandalous behavior we hear about on a day to day basis, trusting ANYBODY seems like a big joke. How are you expected to trust your mate when your neighbors who have been together for more than 15 years have just announced they are getting a divorce and you were told it is due to infidelity? Or you have a friend or acquaintance who is in a "committed" relationship, but he/she loves telling you about all the wild crazy nights he/she has with numerous other people? Or worse even, thinking about your cousin who was in what seemed to be in a very happy marriage until his/her spouse just vanished and left him/her with the kids? Those are just a few examples of all the craziness we witness each day from those around us and I am certain it often makes us wonder how we can trust and believe that anyone is genuine and real in our own lives and relationships. And that brings me to my question;should trust be given or earned? Is it fair to make your make mate prove him or herself to you when they have done nothing to show themselves untrustworthy in the first place? Is there a happy medium where you can give a little trust, but not fully trust until your S.O. proves they are worthy? Here is what I think. People are people and that will never change, but each person is their own person entitled to being treated fairly unless they show you otherwise. Just because you know of a person who trusted someone else and that situation ended badly doesn't mean that will happen to you. And just because a person was one way in the past doesn't always mean they are that way now. PEOPLE CAN CHANGE!